1. Technical Field
The present invention relates in general to a method and system for using color and highlighting to display a tree view display. More particularly, the present invention relates to a system and method for using different values of color and/or highlighting providing a non-indented, layered representation of tree view data.
2. Description of the Related Art
Computer systems in general and International Business Machines (IBM) compatible personal computer systems in particular have attained widespread use for providing computer power to many segments of today's modern society. Systems with microprocessors are finding themselves in an array of smaller and more specialized objects that previously were largely untouched by computer technology. These devices are sometimes called “pervasive computing systems” because of their appearance as both traditionally computerized devices, such as desktop computers, tower computers, and portable computers, as well as newly computerized devices such as telephones, appliances, automobiles, and other devices. Pervasive computing devices generally include a system processor and associated volatile and non-volatile memory, a display area, input means, and often interfaces, such as a network interface or modem, to other computing devices.
One of the distinguishing characteristics of these systems is the use of a system board to electrically connect these components together. Pervasive computing devices are “information handling systems” which are designed primarily to give independent computing power to a single user, or a group of users in the case of networked computing devices. Pervasive computing devices are often inexpensively priced for purchase by individuals or businesses. A pervasive computing device may also include one or more I/O devices (i.e. peripheral devices) which are coupled to the system processor and which perform specialized functions. Examples of I/O devices include modems, sound and video devices or specialized communication devices. Nonvolatile storage devices such as hard disks, CD-ROM drives and magneto-optical drives are also considered to be peripheral devices. Pervasive computing devices are often linked to computing systems and other pervasive computing devices using a network, such as a local area network (LAN), wide area network (WAN), or other type of network such as the Internet. By linking to computers including pervasive computing devices, a pervasive computing device can use resources owned by another computing device. These resources can include files stored on nonvolatile storage devices and resources such as printers.
Pervasive computing devices are often designed to perform a specialized function that has native applications related to the function being performed. For example, a cellular telephone may be a pervasive computing device and may have a telephone directory as a native application. The telephone directory application can store names and phone numbers the user of the cellular phone wishes to store for easy retrieval. Because pervasive computing devices are often portable devices, such as a “personal digital assistant” (“PDA”) or mobile telephones. As a portable device, or as a device incorporated within a larger appliance, pervasive computing devices may have constrained displays in terms of both resolution and screen size. One challenge in using devices with constrained screens is being able to navigate through layered information.
One way in which layered, or hierarchical, information is presented is by using a “tree view” control to display the information to the user. A tree view control is a window that displays a hierarchical list of items, such as the headings in a document, the entries in an index, or the files and directories on a disk. Items displayed often include a label and an optional bitmapped image, and each item can have a list of subitems associated with it. By clicking an item, the user can expand or collapse the associated list of subitems. FIG. 1a shows a traditional tree view control including how items and subitems are displayed in relation to one another.
Traditional tree view window 100 shows example directories stored on a disk. Disk item 105, also called the “root directory,” includes a bitmap representing a drive and a label (“Disk (c:)”) corresponding to the disk. Two high level directories, directory 110 (“Parent A”) and directory 130 (“Parent B”) are shown within the root directory. The hierarchical structure of the information is depicted by showing the directories under the root directory and indented horizontally from the horizontal position of the root directory. Likewise, subdirectories of the two high level directories are shown under the respective high level directory and further indented horizontally from the horizontal position of the parent directory. For example, child directory 115 is shown below parent directory 110 as well as indented horizontally from the horizontal starting position of parent directory 110. Similarly, child directory 135 is shown below parent directory 130 as well as indented horizontally from the horizontal starting position of parent directory 130. Because any item can include subitems, the level of data shown, and the corresponding visual depth shown in the vertical and horizontal displacement, is virtually limitless.
As shown, child directory 115 has two subdirectories (grandchild directories 120 and 125) and child directory 135 has two subdirectories (grandchild directories 140 and 145). The grandchild directories, and their respective subdirectories, can have further subdirectories until all the data needed to be displayed is shown. If the horizontal displacement of a subitem is outside the window area (tree view window 100), a horizontal scroll bar is often placed on the bottom of the window to allow the user to scroll the display to show higher level items on the left side of the window or lower level windows on the right side of the window. Scrolling between high and low level information is challenging to the user because the visual relationship between data items is weakened when only high or low level information can be seen at a given time.
This challenge is exacerbated when the resources of the pervasive computing device are constrained. For example, because of the small form factor the display is often smaller than in monitors attached to traditional desktop systems. This constraint may prevent the pervasive computing device from displaying more than one or two layers in a traditional tree view control.
What is needed, therefore, is a way to display hierarchical relationships between items in a flat tree without needing to provide horizontal displacements to communicate the level of a particular item and its relationship with other items being displayed.